Various types of components, such as electronic components, electromechanical components, and so forth can generate heat (e.g., self-heating) when in operation. The generation of heat during operation can, in some instances, cause can irreversible damage to the components. In some known systems, measuring a temperature of a component susceptible to heat damage can be difficult to perform directly. In some systems, measuring a temperature of a component can be expensive and/or impossible.
As an example, a speaker can be configured to convert electrical energy into acoustic energy and thermal energy. Specifically, a speaker voice coil can interact with magnetic circuitry to cause movement of a diaphragm, which produces sounds, when current is applied to the leads of the speaker voice coil. Applying current (e.g., excessive current) to the voice coil can cause the temperature of components of speaker to rise due to, for example, inefficiencies in the speaker. Heating of the speaker can result in melting of components, sound distortion, thermal compression of an audio signal, thermal fatigue/degradation, mechanical failure, irreversible changes to the magnetic properties of some components of the speaker, and/or so forth. The heating of the speaker can be exacerbated when speaker is driven to generate sounds at a relatively high volume. As another example, mechanical failure can occur when excessive power causes a speaker voice coil to move far enough that it strikes another portion of the speaker or causes separation of portions of the speaker voice coil from a diaphragm of the speaker. In some instances, excessive power applied to the speaker can cause misalignment of portions of the speaker, tearing of the diaphragm, and/or so forth. These types of events that can cause mechanical damage can be referred to as excess-excursion or over-excursion events.
Known modeling and/or measurements techniques may not be sufficient to protect a speaker from thermally-related damage, especially when some characteristics of the speaker are not known, well-quantified, or directly measurable. For example, variations in processes used to produce a speaker can result in relatively inaccurate and/or uncalibrated protection techniques. Accordingly, measuring the temperature of the speaker can be difficult, and consequently, protecting the speaker from thermally-related damage may not be performed in a desirable fashion. In addition, known modeling, detection, prevention, and/or measurements techniques may not be sufficient to protect a speaker from mechanical damage, such as that described above, in response to excessive power. Some known techniques, even if they may provide a desirable level of protection, may be relatively inefficient and/or too expensive to implement in some applications. Thus, a need exists for systems, methods, and apparatus to address the shortfalls of present technology and to provide other new and innovative features.